This invention relates to shear thinning ethylene/α-olefin (EAO) interpolymers. The interpolymers have a Processing Rheology Ratio (PRR) of at least 4, an indication that long chain branching (LCB) is present. The interpolymers attain such a PRR in the absence of a conventional LCB monomer such as norbornadiene (NBD). The alpha-olefin (α-olefin) suitably contains three to 20 carbon atoms (C3-C20) and is preferably propylene (C3), 1-butene, 1-hexene or 1-octene (C8). The interpolymers desirably include a diene (diolefin) monomer, preferably a nonconjugated diene monomer such as 5-ethylidene-2-norbornene (ENB). The diene-containing EAO interpolymers are generically referred to as “EAODM interpolymers”. EAO and EAODM interpolymers are collectively referred to as “EAO(D)M interpolymers”. This invention also relates to preparation of such interpolymers, compositions that include such interpolymers and articles of manufacture that include at least one part or portion fabricated from such interpolymers or compositions.